Atraumatic stapling head features for circular surgical stapler

ABSTRACT

An apparatus includes a body, a shaft assembly, a stapling head assembly, and an anvil. The stapling head assembly includes an annular deck member, a plurality of staples, and a driver. The deck member includes a deck surface that has a curved profile defined by a curve extending from the inner diameter of the deck member to the outer diameter of the deck member. The deck member further includes an outer array of staple openings and an inner array of staple openings. The driver is operable to drive the staples through the staple openings. The anvil is operable to compress tissue against the first deck surface.

PRIORITY

This application is a continuation of U.S. patent application Ser. No.17/459,056, filed Aug. 27, 2021 and published as U.S. Pub. No.2022/0047265 on Feb. 17, 2022, which is a continuation of U.S. patentapplication Ser. No. 16/117,600, filed Aug. 30, 2018 and issued as U.S.Pat. No. 11,191,541 on Dec. 7, 2021, which is a continuation of U.S.patent application Ser. No. 15/350,593, filed Nov. 14, 2016 and issuedas U.S. Pat. No. 10,542,981 on Jan. 28, 2020.

BACKGROUND

In some surgical procedures (e.g., colorectal, bariatric, thoracic,etc.), portions of a patient's digestive tract (e.g., thegastrointestinal tract and/or esophagus, etc.) may be cut and removed toeliminate undesirable tissue or for other reasons. Once the tissue isremoved, the remaining portions of the digestive tract may be coupledtogether in an end-to-end anastomosis. The end-to-end anastomosis mayprovide a substantially unobstructed flow path from one portion of thedigestive tract to the other portion of the digestive tract, withoutalso providing any kind of leaking at the site of the anastomosis.

One example of an instrument that may be used to provide an end-to-endanastomosis is a circular stapler. Some such staplers are operable toclamp down on layers of tissue, cut through the clamped layers oftissue, and drive staples through the clamped layers of tissue tosubstantially seal the layers of tissue together near the severed endsof the tissue layers, thereby joining the two severed ends of theanatomical lumen together. The circular stapler may be configured tosever the tissue and seal the tissue substantially simultaneously. Forinstance, the circular stapler may sever excess tissue that is interiorto an annular array of staples at an anastomosis, to provide asubstantially smooth transition between the anatomical lumen sectionsthat are joined at the anastomosis. Circular staplers may be used inopen procedures or in endoscopic procedures. In some instances, aportion of the circular stapler is inserted through a patient'snaturally occurring orifice.

Examples of circular staplers are described in U.S. Pat. No. 5,205,459,entitled “Surgical Anastomosis Stapling Instrument,” issued Apr. 27,1993; U.S. Pat. No. 5,271,544, entitled “Surgical Anastomosis StaplingInstrument,” issued Dec. 21, 1993; U.S. Pat. No. 5,275,322, entitled“Surgical Anastomosis Stapling Instrument,” issued Jan. 4, 1994; U.S.Pat. No. 5,285,945, entitled “Surgical Anastomosis Stapling Instrument,”issued Feb. 15, 1994; U.S. Pat. No. 5,292,053, entitled “SurgicalAnastomosis Stapling Instrument,” issued Mar. 8, 1994; U.S. Pat. No.5,333,773, entitled “Surgical Anastomosis Stapling Instrument,” issuedAug. 2, 1994; U.S. Pat. No. 5,350,104, entitled “Surgical AnastomosisStapling Instrument,” issued Sep. 27, 1994; and U.S. Pat. No. 5,533,661,entitled “Surgical Anastomosis Stapling Instrument,” issued Jul. 9,1996; and U.S. Pat. No. 8,910,847, entitled “Low Cost Anvil Assembly fora Circular Stapler,” issued Dec. 16, 2014. The disclosure of each of theabove-cited U.S. Patents is incorporated by reference herein.

Some circular staplers may include a motorized actuation mechanism.Examples of circular staplers with motorized actuation mechanisms aredescribed in U.S. Pub. No. 2015/0083772, entitled “Surgical Stapler withRotary Cam Drive and Return,” published Mar. 26, 2015, now abandoned;U.S. Pub. No. 2015/0083773, entitled “Surgical Stapling Instrument withDrive Assembly Having Toggle Features,” published Mar. 26, 2015, issuedas U.S. Pat. No. 9,936,949 on Apr. 10, 2018; U.S. Pub. No. 2015/0083774,entitled “Control Features for Motorized Surgical Stapling Instrument,”published Mar. 26, 2015, issued as U.S. Pat. No. 9,907,552 on Mar. 6,2018; and U.S. Pub. No. 2015/0083775, entitled “Surgical Stapler withRotary Cam Drive,” published Mar. 26, 2015, issued as U.S. Pat. No.9,713,469 on Jul. 25, 2017. The disclosure of each of the above-citedU.S. Patent Publications is incorporated by reference herein.

While various kinds of surgical stapling instruments and associatedcomponents have been made and used, it is believed that no one prior tothe inventor(s) has made or used the invention described in the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims which particularly pointout and distinctly claim this technology, it is believed this technologywill be better understood from the following description of certainexamples taken in conjunction with the accompanying drawings, in whichlike reference numerals identify the same elements and in which:

FIG. 1 depicts a perspective view of an exemplary circular stapler;

FIG. 2 depicts a perspective view of the circular stapler of FIG. 1 ,with a battery pack removed from a handle assembly and an anvil removedfrom a stapling head assembly;

FIG. 3 depicts a perspective view of the anvil of the circular staplerof FIG. 1 ;

FIG. 4 depicts a perspective view of the stapling head assembly of thecircular stapler of FIG. 1 ;

FIG. 5 depicts an exploded perspective view of the stapling headassembly of FIG. 4 ;

FIG. 6 depicts an exploded perspective view of the circular stapler ofFIG. 1 , with portions of the shaft assembly shown separately from eachother;

FIG. 7A depicts a cross-sectional side view of the anvil of FIG. 3positioned within a first section of a digestive tract and the staplinghead assembly of FIG. 4 positioned in a second section of the digestivetract, with the anvil separated from the stapling head assembly;

FIG. 7B depicts a cross-sectional side view of the anvil of FIG. 3positioned within the first section of the digestive tract and thestapling head assembly of FIG. 4 positioned in the second section of thedigestive tract, with the anvil secured to the stapling head assembly;

FIG. 7C depicts a cross-sectional side view of the anvil of FIG. 3positioned within the first section of the digestive tract and thestapling head assembly of FIG. 4 positioned in the second section of thedigestive tract, with the anvil retracted toward the stapling headassembly to thereby clamp tissue between the anvil and the stapling headassembly;

FIG. 7D depicts a cross-sectional side view of the anvil of FIG. 3positioned within the first section of the digestive tract and thestapling head assembly of FIG. 4 positioned in the second section of thedigestive tract, with the stapling head assembly actuated to sever andstaple the clamped tissue;

FIG. 7E depicts a cross-sectional side view of the first and secondsections of the digestive tract of FIG. 7A joined together at anend-to-end anastomosis;

FIG. 8 depicts a partial perspective view of the stapling head assemblyand shaft assembly of the circular stapler of FIG. 1 inserted in apatient's colon, with the stapling head assembly positioned near thepatient's sacrum, and with the patient's anatomy shown in cross-section;

FIG. 9 depicts a partial perspective view of the stapling head assemblyand shaft assembly of the circular stapler of FIG. 1 inserted in apatient's colon, with the stapling head assembly engaging a fold of thecolon tissue, and with the patient's anatomy shown in cross-section;

FIG. 10 depicts a perspective view of an exemplary alternative staplinghead assembly that may be incorporated into the circular stapler of FIG.1 ;

FIG. 11 depicts a top plan view of a deck member of the stapling headassembly of FIG. 10 ;

FIG. 12 depicts a partial cross-sectional view of another exemplaryalternative stapling head assembly that may be incorporated into thecircular stapler of FIG. 1 ;

FIG. 13 depicts a partial perspective view of another exemplaryalternative stapling head assembly that may be incorporated into thecircular stapler of FIG. 1 ;

FIG. 14 depicts a partial cross-sectional view of the stapling headassembly of FIG. 13 , taken along line 14-14 of FIG. 13 ;

FIG. 15 depicts a partial cross-sectional view of the stapling headassembly of FIG. 13 , taken along line 15-15 of FIG. 13 ;

FIG. 16 depicts a partial cross-sectional view of another exemplaryalternative stapling head assembly that may be incorporated into thecircular stapler of FIG. 1 ;

FIG. 17 depicts a perspective view of another exemplary alternative deckmember that may be incorporated into the stapling head assembly of FIG.4 ;

FIG. 18 depicts a perspective view of another exemplary alternative deckmember that may be incorporated into the stapling head assembly of FIG.4 ;

FIG. 19 depicts a top plan view of another exemplary alternativestapling head assembly that may be incorporated into the circularstapler of FIG. 1 ;

FIG. 20 depicts a partial perspective view of the stapling head assemblyof FIG. 19 ;

FIG. 21 depicts a partial cross-sectional view of an exemplary anvilcompressing tissue against the stapling head assembly of FIG. 19 ;

FIG. 22 depicts a partial cross-sectional view of an exemplaryalternative anvil compressing tissue against an exemplary alternativestapling head assembly that may be incorporated into the circularstapler of FIG. 1 ;

FIG. 23 depicts a cross-sectional view of the tissue of FIG. 22 afterthe stapling head assembly of FIG. 22 has been actuated and removed withthe anvil of FIG. 22 , leaving behind the tissue in a severed andstapled state;

FIG. 24 depicts a partial perspective view of another exemplaryalternative stapling head assembly that may be incorporated into thecircular stapler of FIG. 1 ;

FIG. 25 depicts a partial cross-sectional view of the stapling headassembly of FIG. 24 ;

FIG. 26 depicts a partial cross-sectional view of an exemplary anvilcompressing tissue against the stapling head assembly of FIG. 24 ;

FIG. 27 depicts a partial perspective view of another exemplaryalternative stapling head assembly that may be incorporated into thecircular stapler of FIG. 1 ;

FIG. 28 depicts a partial cross-sectional view of the stapling headassembly of FIG. 27 ; and

FIG. 29 depicts a partial perspective view of another exemplaryalternative stapling head assembly that may be incorporated into thecircular stapler of FIG. 1 .

The drawings are not intended to be limiting in any way, and it iscontemplated that various embodiments of the technology may be carriedout in a variety of other ways, including those not necessarily depictedin the drawings. The accompanying drawings incorporated in and forming apart of the specification illustrate several aspects of the presenttechnology, and together with the description serve to explain theprinciples of the technology; it being understood, however, that thistechnology is not limited to the precise arrangements shown.

DETAILED DESCRIPTION

The following description of certain examples of the technology shouldnot be used to limit its scope. Other examples, features, aspects,embodiments, and advantages of the technology will become apparent tothose skilled in the art from the following description, which is by wayof illustration, one of the best modes contemplated for carrying out thetechnology. As will be realized, the technology described herein iscapable of other different and obvious aspects, all without departingfrom the technology. Accordingly, the drawings and descriptions shouldbe regarded as illustrative in nature and not restrictive.

I. Overview of Exemplary Circular Stapling Surgical Instrument

FIGS. 1-2 depict an exemplary surgical circular stapling instrument (10)that may be used to provide an end-to-end anastomosis between twosections of an anatomical lumen such as a portion of a patient'sdigestive tract. Instrument (10) of this example comprises a handleassembly (100), a shaft assembly (200), a stapling head assembly (300),an anvil (400), and a removable battery pack (120). Each of thesecomponents will be described in greater detail below. It should beunderstood that, in addition to or in lieu of the following, instrument(10) may be further constructed and operable in accordance with at leastsome of the teachings of U.S. patent application Ser. No. 14/751,612,entitled “Method of Applying an Annular Array of Staples to Tissue,”filed Jun. 26, 2015, issued as U.S. Pat. No. 10,478,189 on Nov. 19,2019; U.S. Pat. Nos. 5,205,459; 5,271,544; 5,275,322; 5,285,945;5,292,053; 5,333,773; 5,350,104; 5,533,661; and/or U.S. Pat. No.8,910,847, the disclosures of which are incorporated by referenceherein. Still other suitable configurations will be apparent to one ofordinary skill in the art in view of the teachings herein.

A. Exemplary Tissue Engagement Features of Circular Stapling Instrument

As best seen in FIG. 3 , anvil (400) of the present example comprises ahead (410) and a shank (420). Head (410) includes a proximal surface(412) that defines a plurality of staple forming pockets (414). Stapleforming pockets (414) are arranged in two concentric annular arrays inthe present example. Staple forming pockets (414) are configured todeform staples as the staples are driven into staple forming pockets(414) (e.g., deforming a generally “U” shaped staple into a “B” shape asis known in the art). Shank (420) defines a bore or lumen (422) andincludes a pair of pivoting latch members (430) positioned in bore(422). Each latch member (430) includes features that allows anvil (400)to be removably secured to a trocar (330) of stapling head assembly(300) as will be described in greater detail below. It should beunderstood, however, that anvil (400) may be removably secured to atrocar (330) using any other suitable components, features, ortechniques.

Stapling head assembly (300) is located at the distal end of shaftassembly (200). As shown in FIGS. 1-2 , anvil (400) is configured toremovably couple with shaft assembly (200), adjacent to stapling headassembly (300). As will be described in greater detail below, anvil(400) and stapling head assembly (300) are configured to cooperate tomanipulate tissue in three ways, including clamping the tissue, cuttingthe tissue, and stapling the tissue. As best seen in FIGS. 4-5 ,stapling head assembly (300) of the present example comprises a tubularcasing (310) housing a slidable staple driver member (350). Acylindraceous inner core member (312) extends distally within tubularcasing (310). Tubular casing (310) is fixedly secured to an outer sheath(210) of shaft assembly (200), such that tubular casing (310) serves asa mechanical ground for stapling head assembly (300).

Trocar (330) is positioned coaxially within inner core member (312) oftubular casing (310). Trocar (330) is operable to translate distally andproximally relative to tubular casing (310) in response to rotation of aknob (130) located at the proximal end of handle assembly (100). Trocar(330) comprises a shaft (332) and a head (334). Head (334) includes apointed tip (336) and an inwardly extending proximal surface (338). Head(334) and the distal portion of shaft (332) are configured for insertionin bore (422) of anvil (420). Proximal surface (338) is configured tocomplement features of latch members (430) to provide a snap fit betweenanvil (400) and trocar (330).

Staple driver member (350) is operable to actuate longitudinally withintubular casing (310) in response to activation of motor (160) as will bedescribed in greater detail below. Staple driver member (350) includestwo distally presented concentric annular arrays of staple drivers(352). Staple drivers (352) are arranged to correspond with thearrangement of staple forming pockets (414) described above. Thus, eachstaple driver (352) is configured to drive a corresponding staple into acorresponding staple forming pocket (414) when stapling head assembly(300) is actuated. Staple driver member (350) also defines a bore (354)that is configured to coaxially receive core member (312) of tubularcasing (310).

A cylindraceous knife member (340) is coaxially positioned within stapledriver member (350). Knife member (340) includes a distally presented,sharp circular cutting edge (342). Knife member (340) is sized such thatknife member (340) defines an outer diameter that is smaller than thediameter defined by the inner annular array of staple drivers (352).Knife member (340) also defines an opening that is configured tocoaxially receive core member (312) of tubular casing (310).

A deck member (320) is fixedly secured to tubular casing (310). Deckmember (320) includes a distally presented deck surface (322) definingtwo concentric annular arrays of staple openings (324). Staple openings(324) are arranged to correspond with the arrangement of staple drivers(352) and staple forming pockets (414) described above. Thus, eachstaple opening (324) is configured to provide a path for a correspondingstaple driver (352) to drive a corresponding staple through deck member(320) and into a corresponding staple forming pocket (414) when staplinghead assembly (300) is actuated. It should be understood that thearrangement of staple openings (322) may be modified just like thearrangement of staple forming pockets (414) as described above. Itshould also be understood that various structures and techniques may beused to contain staples within stapling head assembly (300) beforestapling head assembly (300) is actuated. Deck member (320) defines aninner diameter that is just slightly larger than the outer diameterdefined by knife member (340). Deck member (320) is thus configured toallow knife member (340) to translate distally to a point where cuttingedge (342) is distal to deck surface (322).

FIG. 6 shows various components of shaft assembly (200), which extendsdistally from handle assembly (100) and couples components of staplinghead assembly (300) with components of handle assembly (100). Inparticular, and as noted above, shaft assembly (200) includes an outersheath (210) that extends between handle assembly (100) and tubularcasing (310). In the present example, outer sheath (210) is rigid andincludes a preformed curved section (212) that is configured tofacilitate positioning of stapling head assembly (300) within apatient's colon as described below. Curved section (212) includes aninner curve (216) and an outer curve (214).

Shaft assembly (200) further includes a trocar actuation rod (220) and atrocar actuation band assembly (230). The distal end of trocar actuationband assembly (230) is fixedly secured to the proximal end of trocarshaft (332). The proximal end of trocar actuation band assembly (230) isfixedly secured to the distal end of trocar actuation rod (220), suchthat trocar (330) will translate longitudinally relative to outer sheath(210) in response to translation of trocar actuation band assembly (230)and trocar actuation rod (220) relative to outer sheath (210). Trocaractuation band assembly (230) is configured to flex such that trocaractuation band assembly (230) may follow along the preformed curve inshaft assembly (200) as trocar actuation band assembly (230) istranslated longitudinally relative to outer sheath (210). However,trocar actuation band assembly (230) has sufficient column strength andtensile strength to transfer distal and proximal forces from trocaractuation rod (220) to trocar shaft (332). Trocar actuation rod (220) isrigid. A clip (222) is fixedly secured to trocar actuation rod (220) andis configured to cooperate with complementary features within handleassembly (100) to prevent trocar actuation rod (220) from rotatingwithin handle assembly (100) while still permitting trocar actuation rod(220) to translate longitudinally within handle assembly (100). Trocaractuation rod (220) further includes a coarse helical threading (224)and a fine helical threading (226).

Shaft assembly (200) further includes a stapling head assembly driver(240) that is slidably received within outer sheath (210). The distalend of stapling head assembly driver (240) is fixedly secured to theproximal end of staple driver member (350). The proximal end of staplinghead assembly driver (240) is secured to a drive bracket (250) via a pin(242). It should therefore be understood that staple driver member (350)will translate longitudinally relative to outer sheath (210) in responseto translation of stapling head assembly driver (240) and drive bracket(250) relative to outer sheath (210). Stapling head assembly driver(240) is configured to flex such that stapling head assembly driver(240) may follow along the preformed curve in shaft assembly (200) asstapling head assembly driver (240) is translated longitudinallyrelative to outer sheath (210). However, stapling head assembly driver(240) has sufficient column strength to transfer distal forces fromdrive bracket (250) to staple driver member (350).

B. Exemplary User Input Features of Circular Stapling Instrument

As shown in FIG. 1 , handle assembly (100) includes a pistol grip (112)and several components that are operable to actuate anvil (400) andstapling head assembly (300). In particular, handle assembly (100)includes knob (130), a safety trigger (140) a firing trigger (150), amotor (160), and a motor activation module (180). Knob (130) is coupledwith trocar actuation rod (220) via a nut (not shown), such that coarsehelical threading (224) will selectively engage a thread engagementfeature within the interior of the nut; and such that fine helicalthreading (226) will selectively engage a thread engagement featurewithin the interior of knob (130). These complementary structures areconfigured such that trocar actuation rod (220) will first translateproximally at a relatively slow rate, then translate proximally at arelatively fast rate, in response to rotation of knob (130).

It should be understood that when anvil (400) is coupled with trocar(330), rotation of knob (130) will provide corresponding translation ofanvil relative to stapling head assembly (300). It should also beunderstood that knob (130) may be rotated in a first angular direction(e.g., clockwise) to retract anvil (400) toward stapling head assembly(300); and in a second angular direction (e.g., counterclockwise) toadvance anvil (400) away from stapling head assembly (300). Knob (130)may thus be used to adjust the gap distance between opposing surfaces(412, 322) of anvil (400) and stapling head assembly (300) until asuitable gap distance has been achieved.

In the present example, handle assembly (100) comprises a user feedbackfeature (114) that is configured to provide the operator with visualfeedback indicating the positioning of anvil (400) in relation tostapling assembly (300). The operator may thus observe user feedbackfeature (114) while rotating knob (130), to confirm whether the suitablegap distance between anvil (400) and stapling assembly (300) has beenachieved. By way of example only, user feedback feature (114) may beconfigured and operable in accordance with at least some of theteachings of U.S. patent application Ser. No. 14/751,612, entitled“Method of Applying an Annular Array of Staples to Tissue,” filed Jun.26, 2015, issued as U.S. Pat. No. 10,478,189 on Nov. 19, 2019, thedisclosure of which is incorporated by reference herein. Other suitableforms of providing user feedback will be apparent to those of ordinaryskill in the art in view of the teachings herein.

Firing trigger (150) is operable to activate motor (160) to therebyactuate stapling head assembly (300). Safety trigger (140) is operableto selectively block actuation of firing trigger (150) based on thelongitudinal position of anvil (400) in relation to stapling headassembly (300). Handle assembly (100) also includes components that areoperable to selectively lock out both triggers (140, 150) based on theposition of anvil (400) relative to stapling head assembly (300). Whentriggers (140, 150) are locked out, firing trigger (150) is preventedfrom initiating actuation of stapling head assembly (300). Thus, trigger(150) is only operable to initiate actuation of stapling head assembly(300) when the position of anvil (400) relative to stapling headassembly (300) is within a predefined range.

In the present example, firing trigger (150) of the present exampleincludes an integral actuation paddle, such as the paddle shown anddescribed in U.S. patent application Ser. No. 14/751,231, entitled“Surgical Stapler with Reversible Motor,” filed Jun. 26, 2015, issued asU.S. Pat. No. 10,456,134 on Oct. 29, 2019, the disclosure of which isincorporated by reference herein. The paddle is configured to actuate aswitch of motor activation module (180) (FIG. 1 ) when firing trigger(150) is pivoted to a fired position. Motor activation module (180) isin communication with battery pack (120) and motor (160), such thatmotor activation module (180) is configured to provide activation ofmotor (160) with electrical power from battery pack (120) in response tothe paddle actuating the switch of motor activation module (180). Thus,motor (160) will be activated when firing trigger (150) is pivoted. Thisactivation of motor (160) will actuate stapling head assembly (300) asdescribed in greater detail below.

Battery pack (120) is operable to provide electrical power to a motor(160) as noted above. Battery pack (120) may be removably coupled withhandle assembly (100) through a snap fit or in any other suitablefashion. It should be understood that battery pack (120) and handleassembly (100) may have complementary electrical contacts, pins andsockets, and/or other features that provide paths for electricalcommunication from battery pack (120) to electrically powered componentsin handle assembly (100) when battery pack (120) is coupled with handleassembly (100). It should also be understood that, in some versions,battery pack (120) is unitarily incorporated within handle assembly(100) such that battery back (120) cannot be removed from handleassembly (100).

C. Exemplary Anastomosis Procedure with Circular Stapling Instrument

FIGS. 7A-7E show instrument (10) being used to form an anastomosis (70)between two tubular anatomical structures (20, 40). By way of exampleonly, the tubular anatomical structures (20, 40) may comprise sectionsof a patient's esophagus, sections of a patient's colon, other sectionsof the patient's digestive tract, or any other tubular anatomicalstructures. In some versions, one or more diseased portions of apatient's colon are removed, with the tubular anatomical structures (20,40) of FIGS. 7A-7E representing the remaining severed portions of thecolon.

As shown in FIG. 7A, anvil (400) is positioned in one tubular anatomicalstructure (20) and stapling head assembly (300) is positioned in anothertubular anatomical structure (40). In versions where tubular anatomicalstructures (20, 40) comprise sections of a patient's colon, staplinghead assembly (300) may be inserted via the patient's rectum. It shouldalso be understood that the procedure depicted in FIGS. 7A-7E is an opensurgical procedure, though the procedure may instead be performedlaparoscopically. By way of example only, the surgical procedure may beperformed laparoscopically in accordance with at least some of theteachings of U.S. Pub. No. 2016/0100837, entitled “Surgical StaplingApparatus Comprising a Tissue Stop,” published Apr. 14, 2016, issued asU.S. Pat. No. 10,076,325 on Sep. 18, 2018, the disclosure of which isincorporated by reference herein; and/or U.S. patent application Ser.No. 14/864,310, entitled “Apparatus and Method for Forming a Staple Linewith Trocar Passageway,” filed Sep. 24, 2015, issued as U.S. Pat. No.10,485,548 on Nov. 26, 2019, the disclosure of which is incorporated byreference herein. Various other suitable ways in which instrument (10)may be used to form an anastomosis (70) in a laparoscopic procedure willbe apparent to those of ordinary skill in the art in view of theteachings herein.

As shown in FIG. 7A, anvil (400) is positioned in tubular anatomicalstructure (20) such that shank (420) protrudes from the open severed end(22) of tubular anatomical structure (20). A purse-string suture (30) isprovided about a mid-region of shank (420) to generally secure theposition of anvil (400) in tubular anatomical structure (20). Similarly,stapling head assembly (300) is positioned in tubular anatomicalstructure (40) such that trocar (330) protrudes from the open severedend (42) of tubular anatomical structure (20). A purse-string suture(50) is provided about a mid-region of shaft (332) to generally securethe position of stapling head assembly (300) in tubular anatomicalstructure (40).

Next, anvil (400) is secured to trocar (330) by inserting trocar (330)into bore (422) as shown in FIG. 7B. Latch members (430) engage head(334) of trocar (330), thereby providing a secure fit between anvil(400) and trocar (330). The operator then rotates knob (130) whileholding handle assembly (100) stationary via pistol grip (112). Thisrotation of knob (130) causes trocar (330) and anvil (400) to retractproximally, as described above. As shown in FIG. 7C, this proximalretraction of trocar (330) and anvil (400) compresses the tissue oftubular anatomical structures (20, 40) between surfaces (412, 322) ofanvil (400) and stapling head assembly (300). The operator observes userfeedback feature (114) to determine whether the gap distance (d) betweenopposing surfaces (412, 322) of anvil (400) and stapling head assembly(300) is appropriate; and makes any necessary adjustments via knob(130).

Once the operator has appropriately set the gap distance (d) via knob(130), the operator actuates safety trigger (140) to enable actuation offiring trigger (150). The operator then actuates firing trigger (150).This actuation of firing trigger (150) in turn actuates a switch ofmotor activation module (180), which in turn activates motor (160) tothereby actuate stapling head assembly (300) by driving knife member(340) and staple driver member (350) distally as shown in FIG. 7D. Asknife member (340) translates distally, cutting edge (342) of knifemember (340) cooperates with inner edge (416) of anvil (400), therebyshearing excess tissue that is positioned within annular recess (418) ofanvil (400) and the interior of knife member (340).

As shown in FIG. 4 , anvil (400) of the present example includes abreakable washer (417) within annular recess (418). This washer (417) isbroken by knife member (340) when knife member (340) completes a fulldistal range of motion from the position shown in FIG. 7C to theposition shown in FIG. 7D. The drive mechanism for knife member (340)may provide an increasing mechanical advantage as knife member (340)reaches the end of its distal movement, thereby providing greater forceby which to break washer (417). Of course, breakable washer (417) may beomitted entirely in some versions. In versions where washer (417) isincluded, it should be understood that washer (417) may also serve as acutting board for knife member (340) to assist in cutting of tissue.Such a cutting technique may be employed in addition to or in lieu ofthe above-noted shearing action between inner edge (416) and cuttingedge (342).

As staple driver member (350) translates distally from the positionshown in FIG. 7C to the position shown in FIG. 7D, staple driver member(350) drives staples (90) through the tissue of tubular anatomicalstructures (20, 40) and into staple forming pockets (414) of anvil(400). Staple forming pockets (414) deform the driven staples (90) intoa “B” shape as is known in the art. The formed staples (90) thus securethe ends of tissue together, thereby coupling tubular anatomicalstructure (20) with tubular anatomical structure (40).

After the operator has actuated stapling head assembly (300) as shown inFIG. 7D, the operator rotates knob (130) to drive anvil (400) distallyaway from stapling head assembly (300), increasing the gap distance (d)to facilitate release of the tissue between surfaces (412, 322). Theoperator then removes instrument (10) from the patient, with anvil (400)still secured to trocar (330). Referring back to the example where thetubular anatomical structures (20, 40) comprise sections of a patient'scolon, instrument (10) may be removed via the patient's rectum. Withinstrument (10) removed, the tubular anatomical structures (20, 40) areleft secured together by two annular arrays of staples (90) at ananastomosis (70) as shown in FIG. 7E. The inner diameter of theanastomosis (70) is defined by the severed edge (60) left by knifemember (340).

II. Exemplary Alternative Stapling Head Assembly

As noted above, in some instances, anatomical structures (20, 40) maycomprise sections of a patient's colon. FIG. 8 shows stapling headassembly (300) and a distal portion of shaft assembly (200) disposed ina patient's colon (C). As shown, stapling head assembly (300) and shaftassembly (200) are inserted via the patient's rectum (R). As also shown,the curvature of curved section (212) is configured to generallycomplement the curvature of the patient's colon (C). Nevertheless, asalso shown in FIG. 8 , there may be instances where deck member (320)tends to compress tissue (T) of the patient's colon (C) against thepatient's sacrum (S) and/or some other substantially rigid anatomicalstructure. Depending on the angle at which the operator has insertedstapling head assembly (300) and shaft assembly (200), and/or dependingon the force that the operator is applying to stapling head assembly(300) and shaft assembly (200) during insertion, the tissue (T) of thepatient's colon (C) may become damaged (e.g., torn) when the tissue (T)is pinched between stapling head assembly (300) and the patient's sacrum(S). In versions where deck member (320) has tissue gripping featuresand/or other protruding features (e.g., staple guidance features, etc.),such features may increase the risk of damage to the tissue (T) of thepatient's colon (C) as stapling head assembly (300) and shaft assembly(200) are being inserted into the patient's colon (C).

Similarly, as shown in FIG. 9 , those of ordinary skill in the art willrecognize that the tissue (T) of the colon (C) defines a plurality offolds (F), and that stapling head assembly (300) may get snagged on suchfolds (F) as stapling head assembly (300) and shaft assembly (200) areinserted in the patient's colon (C). This snagging may also create arisk of damaging the tissue (T) of the patient's colon (C). Again, inversions where deck member (320) has tissue gripping features and/orother protruding features (e.g., staple guidance features, etc.), suchfeatures may increase the risk of damage to the tissue (T) of thepatient's colon (C) as stapling head assembly (300) gets snagged onfolds (F).

It may therefore be desirable to provide a version of stapling headassembly (300) that minimizes the risk of damaging the tissue (T) of thepatient's colon (C) during insertion of stapling head assembly (300) andshaft assembly (200) into the patient's colon (C). Moreover, it may bedesirable to provide a version of stapling head assembly (300) thatincludes features that enhance gripping of tissue during actuation ofstapling head assembly (300), thereby promoting successful tissuecutting and staple deployment, without increasing the risk of damagingthe tissue (T) of the patient's colon (C) during insertion of staplinghead assembly (300) and shaft assembly (200) into the patient's colon(C).

A. Exemplary Deck Member with Flat Zone and Tissue Engagement FeatureZone

FIG. 10 shows an exemplary alternative stapling head assembly (500) thatmay be readily incorporated into stapling instrument in place ofstapling head assembly (300). Except as otherwise described below,stapling head assembly (500) of this example is configured and operablejust like stapling head assembly (300) described above. Stapling headassembly (500) of this example includes a deck member (502) having adeck surface (522) that defines two concentric annular arrays of stapleopenings (524). Staple openings (524) are arranged to correspond withthe arrangement of staple drivers (352) and staple forming pockets (414)described above. Thus, each staple opening (524) is configured toprovide a path for a corresponding staple driver (352) to drive acorresponding staple through deck member (502) and into a correspondingstaple forming pocket (414) when stapling head assembly (500) isactuated. Deck member (502) defines an inner diameter that is justslightly larger than the outer diameter defined by knife member (540).Deck member (502) is thus configured to allow knife member (540) totranslate distally to a point where cutting edge (542) is distal to decksurface (522).

Unlike deck member (320) described above, deck member (502) of thepresent example includes a first zone (510) and a second zone (550).First zone (510) is characterized in that deck surface (522) issubstantially flat within first zone (510). First zone (510) includes anouter edge (520) that has a curved configuration. Outer edge (520) isthus configured to reduce the risk of outer edge (520) snagging ontissue (T) as stapling head assembly (500) is inserted into thepatient's colon (C).

Second zone (550) is characterized in that second zone has a recesseddeck surface (552) with a plurality of stand-off features (560)protruding upwardly from recessed deck surface (552). A steppedtransition (530) is formed at the boundaries between zones (510, 550),thereby providing a step-down from deck surface (522) to recessed decksurface (552). In some versions, transition (530) is orientedperpendicularly relative to surfaces (522, 552), such that transition(530) provides a steep drop-off from deck surface (522) to recessed decksurface (552). In some other versions, transition (530) is orientedobliquely relative to surfaces (522, 552), such that transition (530)provides a sloped transition from deck surface (522) to recessed decksurface (552). Alternatively, transition (530) may have a curvedconfiguration or any other suitable configuration.

Stand-off features (560) each include an outwardly facing surface (562),an outer wall portion (564), and an inner wall portion (566). Outwardlyfacing surfaces (562) are curved to complement the curved configurationof outer edge (520). Outwardly facing surfaces (562) are thus configuredto reduce the risk of stand-off features (560) snagging on tissue (T) asstapling head assembly (500) is inserted into the patient's colon (C).Outer wall portions (564) are configured to wrap partially around theouter array of staple openings (524). Outer wall portions (564) are thusconfigured and positioned to provide guidance to staples (90) exitingthe outer array of staple openings (524). Inner wall portions (564) areconfigured to wrap partially around the inner array of staple openings(524). Inner wall portions (564) are thus configured and positioned toprovide guidance to staples (90) exiting the inner array of stapleopenings (524).

Since each inner wall portion (566) is contiguous with a correspondingouter wall portion (564), and since the inner array of staple openings(524) is angularly offset from the inner array of staple openings (524),each stand-off feature (560) generally has a zig-zag configuration. Inthe present example, the upper edges (568) of stand-off features (560)are located on the same plane as deck surface (522), such that upperedges (568) and deck surface (522) will contact tissue along the sameplane. In other words, while recessed deck surface (552) is recessedrelative to upper edges (568), deck surface (522) is not recessedrelative to upper edges (568). In some other versions, at least aportion of upper edges (568) extends above or below the plane of decksurface (522).

It should also be understood that stand-off features (560) arediscretely formed in the present example, such that gaps are locatedbetween each stand-off feature (560) and the adjacent stand-off features(560). In some other versions, stand-off features (560) are contiguouswith each other.

Second zone (550) also includes an upwardly protruding annular wall(592). Annular wall (592) is flush with deck surface (522). Annular wall(592) is configured to compress a partially annular region of tissueagainst anvil (400), thereby providing assistance for edge (542) ofknife member (540) to shear tissue. Annular wall (592) is contiguous andcoplanar with the inner region of deck surface (522), such that annularwall (592) and deck surface cooperate to compress a fully annular regionof tissue against anvil (400), providing even compression along a fullcircumference of a tissue region. An annular recess (590) is formedbetween annular wall (590) and stand-off features (560). In some otherversions, inner wall portions (566) extend fully to annular wall (590),such that annular wall (590) is connected directly to stand-off features(560) via inner wall portions (566).

It should be understood that the protruding configuration of stand-offfeatures (560) relative to recessed deck surface (552) will providetissue engagement effects in second zone (550) that are not provided infirst zone (510). In particular, when tissue is compressed between deckmember (502) and anvil (400) as described above, portions of thecompressed tissue will enter the recessed areas adjacent to stand-offfeatures (560). By having some of the tissue enter these recessed areas,this may reduce the total pressure that would otherwise be applied tothe tissue if the tissue were being compressed against a consistentlyflat deck surface like deck surface (322). By reducing the totalpressure on the tissue, deck member (502) may reduce the risk of thetissue from becoming fractured by over-compression. In addition toreducing the total pressure on tissue, the entry of tissue portions inrecessed areas adjacent to stand-off features (560) may provide a gripon the compressed tissue that is greater than the grip that couldotherwise be achieved using a consistently flat deck surface like decksurface (322). The enhanced grip of tissue may promote cleaner cuttingby knife member (540) and also promote more successful deployment ofstaples (90) in the tissue. Thus, the presence of stand-off features(560) may both reduce the risk of over-compression of tissue and promotegreater success in cutting and stapling the tissue.

As best seen in FIG. 11 , first zone (510) spans along an angular range(θ) of approximately 90° of the circumference of deck member (502) inthe present example. By way of further example only, first zone (510)may span along an angular range (θ) of less than approximately 90° ofthe circumference of deck member (502). For instance, first zone (510)may span along an angular range (θ) between approximately 30° andapproximately 90° of the circumference of deck member (502); or betweenapproximately 45° and approximately 90° of the circumference of deckmember (502).

As noted above, the entry of tissue into recessed areas adjacent tostand-off features (560) may reduce the risk of over-compression oftissue and promote greater success in cutting and stapling the tissueduring actuation of anvil (400) and stapling head assembly (500).However, this same entry of tissue into recessed areas adjacent tostand-off features (560) may present some risks during insertion ofstapling head assembly (500) and shaft assembly (200) into tissue. Inother words, in variations of deck member (502) where stand-off features(560) are positioned along the full circumference of deck member (502),there may be a tendency for tissue (T) to enter the recessed areasadjacent to stand-off features (560) during insertion of shaft assembly(200) and a stapling head assembly (500) into the patient's colon (C).Any resulting snagging of tissue (T) on stand-off features (560) mayincrease the risk of damage to tissue (T) in the event that the tissue(T) is being pinched against the sacrum (S) as described above withreference to FIG. 8 .

To avoid the above-noted risks that might otherwise be associated withtissue snagging on stand-off features (560) during insertion of shaftassembly (200) and stapling head assembly (500) into the patient's colon(C), first zone (510) is positioned to correspond with outer curve (214)of curved section (212) of shaft assembly (200). As shown in FIG. 8 ,the region of stapling head assembly (300) corresponding to outer curve(214) is the region of stapling head assembly (300) that would tend topinch the tissue (T) against the sacrum (S). Thus, by having first zone(510) in this region, stapling head assembly (500) avoids the risks thatmight otherwise be associated with stand-off features (560) duringinsertion of shaft assembly (200) and stapling head assembly (500) intothe patient's colon (C); while still providing the advantages ofstand-off features (560) in second zone when anvil (400) and staplinghead assembly (500) are actuated.

FIG. 12 shows a portion of an exemplary alternative stapling headassembly (600), which comprises a cylindraceous knife member (640) andan alternative deck member (650). Stapling head assembly (600) isconfigured and operable just like stapling head assembly (500), exceptfor the differences described below. In particular, the angular regionof deck member (650) shown in FIG. 12 corresponds with second zone (550)of deck member (502). It should be understood that deck member (650) mayhave another angular region corresponding with first zone (510) of deckmember (502) (i.e., with a flat deck surface like deck surface (520)).Alternatively, deck member (650) may be configured with the samegeometry as represented in FIG. 12 about the full circumference of deckmember (650). Of course, deck member (650) may have any other kinds ofgeometries and structural configurations along angular regions havingany other arrangements and relationships with the angular regionrepresented in FIG. 12 .

Like deck member (502) described above, deck member (650) of the presentexample includes an inner annular array of staple openings (624) (shownas being closer to knife member (640)) and an outer annular array ofstaple openings (624) (shown as being further from knife member (640)).While only one inner staple opening (624) and one outer staple opening(624) are shown, it should be understood that additional staple openings(624) are provided in inner and outer annularly arrays that areangularly offset relative to each other, just like staple openings (524)of deck member (502).

FIG. 12 also shows a plurality of structural features adjacent to stapleopenings (624). In particular, a first radiused surface (670) is locatedoutboard of outer staple opening (624). A second radiused surface (672)is located between outer and inner staple openings (624). A thirdradiused surface (674) is located inboard of inner staple opening (624).Radiused surfaces (670, 672, 674) all extend along the same curve (B) inthis example. It should be understood that radiused surfaces (670, 672,674) may be defined by a stand-off feature like stand-off feature (560)described above. In other words, stand-off feature (560) described abovemay be modified to provide radiused surfaces (670, 672, 674) of deckmember (650), such that stand-off feature (560) has a generally concavecross-sectional profile along a transverse plane.

A recess (622) is formed outboard of first radiused surface (670), withan angled surface (620) providing the floor of recess (622). The angleof angled surface (620) is oriented along a line (B), which will bereferred to again below.

Deck member (602) also includes an upwardly protruding annular wall(654), similar to annular wall (592) described above. Annular wall (654)extends to a height such that annular wall (654) distally terminates ata position along curve (B), described above. The distal terminationpoint of annular wall (654) is also distal to cutting edge (642) ofknife member (640). It should be understood that annular wall (654) isconfigured to compress a region of tissue against anvil (400), therebyproviding assistance for edge (642) of knife member (640) to sheartissue. A recess (662) is formed outboard of annular wall (654), similarto recess (590) described above. While annular wall (654) provides onesidewall defining recess (662), a sharply sloped wall (676) providesanother sidewall defining recess. Wall (676) is contiguous with thirdradiused surface (674) and provides a steeply sloped curved transitionto an angled surface (660), which provides a floor of recess (662). Theangle of angled surface (660) is oriented along the same line (B) as theangle of angled surface (620) described above.

As can be seen in FIG. 12 , line (B) slopes downwardly from the outerdiameter of stapling head assembly toward the inner diameter of staplinghead assembly. As can also be seen in FIG. 12 , due to the positioningand orientation of line (B), and due to the positioning andconfiguration of curve (A), recess (662) is substantially deeper thanrecess (622). Thus, to the extent that the depth of recesses (622, 620)is proportional to the tissue gripping enhancement provided by recesses(662, 660), recess (662) would provide greater tissue gripping thanrecess (622). Similarly, the manner in which the effective height ofradiused surfaces (670, 672, 674) increases progressively toward theinner diameter of stapling head assembly will also provide increasinglygreater tissue gripping toward the inner diameter of stapling headassembly. Conversely, the relatively shallow depth of recess (622), andthe relatively short height of radiused surface (670), will provideminimized drag against tissue (T) as stapling head assembly (600) isadvanced through the colon (C). The curved profile provided by radiusedsurfaces (670, 672, 674) may also assist in minimizing drag againsttissue (T) as stapling head assembly (600) is advanced through the colon(C).

B. Exemplary Deck Member with Zones Having Differing Tissue EngagementFeature Aggressiveness

FIG. 13 shows a portion of another exemplary alternative stapling headassembly (700), which comprises a cylindraceous knife member (740) andan alternative deck member (702). Stapling head assembly (700) isconfigured and operable just like stapling head assembly (500), exceptfor the differences described below. Stapling head assembly (700) ofthis example includes a deck member (702) with an outer edge (720) thathas a curved configuration. Outer edge (720) is thus configured toreduce the risk of outer edge (720) snagging on tissue (T) as staplinghead assembly (700) is inserted into the patient's colon (C).

Deck member (702) also has deck surfaces (722, 752) that define twoconcentric annular arrays of staple openings (724). Staple openings(724) are arranged to correspond with the arrangement of staple drivers(352) and staple forming pockets (414) described above. Thus, eachstaple opening (724) is configured to provide a path for a correspondingstaple driver (752) to drive a corresponding staple through deck member(700) and into a corresponding staple forming pocket (414) when staplinghead assembly (700) is actuated. Deck member (702) of the presentexample also includes an inner annular wall (754), which protrudesupwardly relative to deck surfaces (722, 752). Annular wall (754)defines an inner diameter that is just slightly larger than the outerdiameter defined by knife member (740). Deck member (702) is thusconfigured to allow knife member (740) to translate distally to a pointwhere cutting edge (742) is distal to deck surfaces (722, 752) andannular wall (754). Annular wall (754) is configured to compress apartially annular region of tissue against anvil (400), therebyproviding assistance for edge (742) of knife member (740) to sheartissue.

Like deck member (502) described above, deck member (702) of the presentexample includes a first zone (710) and a second zone (750). In someversions, first zone (710) spans along an angular range (θ) ofapproximately 45° of the circumference of deck member (702). By way offurther example only, first zone (710) may span along an angular range(θ) of up to approximately 90° of the circumference of deck member(702). For instance, first zone (710) may span along an angular range(θ) between approximately 30° and approximately 90° of the circumferenceof deck member (702); or between approximately 45° and approximately 90°of the circumference of deck member (702).

First zone (710) includes deck surface (722), which is obliquely angledrelative to the longitudinal axis of stapling head assembly (700). Inparticular, as shown in FIG. 15 and as described in greater detailbelow, deck surface (722) slopes downwardly or proximally from outeredge (720) to the radially innermost region of deck surface (722). Insome other versions, deck surface (722) extends along a plane that isperpendicular to the longitudinal axis of stapling head assembly (700).

First zone (710) also includes a plurality of stand-off features (730)protruding upwardly from deck surface (722). Stand-off features (730)each include an outer wall portion (732) and an inner wall portion(736). Outer wall portions (732) are configured to wrap partially aroundthe outer array of staple openings (724). Outer wall portions (732) arethus configured and positioned to provide guidance to staples (90)exiting the outer array of staple openings (724). Inner wall portions(736) are configured to wrap partially around the inner array of stapleopenings (724). Inner wall portions (734) are thus configured andpositioned to provide guidance to staples (90) exiting the inner arrayof staple openings (724). An annular recess (776) is formed betweenannular wall (754) and stand-off features (730). In some other versions,inner wall portions (736) extend fully to annular wall (754), such thatannular wall (754) is connected directly to stand-off features (730) viainner wall portions (736).

Since each inner wall portion (736) is contiguous with a correspondingouter wall portion (732), and since the inner array of staple openings(724) is angularly offset from the inner array of staple openings (724),each stand-off feature (730) generally has a zig-zag configuration. Itshould also be understood that stand-off features (730) are discretelyformed in the present example, such that gaps are located between eachstand-off feature (730) and the adjacent stand-off features (730). Insome other versions, stand-off features (730) are contiguous with eachother.

In the version shown in FIGS. 13-14 , the upper edges (768) of stand-offfeatures (760) are located below the plane of the upper edge of annularwall (754), such that annular wall (754) will contact tissue just beforeupper edges (768) contact the tissue. In some other versions, as shownin FIG. 15 , at least a portion of upper edges (768) are located alongthe same plane as the upper edge of annular wall (754), such that upperedges (768) and annular wall (754) will contact tissue along the sameplane.

Regardless of the relationship between the height of upper edges (768)and the height of annular wall (754), it should be understood that upperedges (768) may have any suitable relationship with deck surface (752).For instance, in the version shown in FIG. 13 , upper edges (738) ofstand-off features (730) are located on the same plane as deck surface(752), such that upper edges (738) and deck surface (752) will contacttissue along the same plane. In other words, while deck surface (752) isrecessed relative to upper edges (768) of stand-off features, decksurface (752) is not recessed relative to upper edges (738) of stand-offfeatures (730). In some other versions, as shown in FIG. 14 , at least aportion of upper edges (738) extends above the plane of deck surface(752). In still other versions, at least a portion of upper edges (738)extends below the plane of deck surface (752).

Second zone (750) also has a plurality of stand-off features (760)protruding upwardly from a deck surface (752). Unlike deck surface (722)of first zone (710), deck surface (752) of second zone (750) extendsalong a plane that is perpendicular to the longitudinal axis of staplinghead assembly (700). As best seen in FIG. 14 , there a sloped transitionsurface (774) provides a transition from deck surface (752) to decksurface (722), such that transition surfaces (774) defined theboundaries between first and second zones (710, 750). While eachtransition surface (774) is sloped in the present example, it should beunderstood that transition surface (774) may have any other suitableconfiguration. For instance, transition surface (774) may provide asteep step-down (e.g., like transition (530) described above), a curvedtransition, or any other suitable kind of transition.

Stand-off features (760) each include an outwardly facing surface (764),an outer wall portion (762), and an inner wall portion (766). Outwardlyfacing surfaces (764) are curved to complement the curved configurationof outer edge (720). Outwardly facing surfaces (762) are thus configuredto reduce the risk of stand-off features (760) snagging on tissue (T) asstapling head assembly (700) is inserted into the patient's colon (C).Outer wall portions (762) are configured to wrap partially around theouter array of staple openings (724). Outer wall portions (762) are thusconfigured and positioned to provide guidance to staples (90) exitingthe outer array of staple openings (724). Inner wall portions (766) areconfigured to wrap partially around the inner array of staple openings(724). Inner wall portions (764) are thus configured and positioned toprovide guidance to staples (90) exiting the inner array of stapleopenings (724). An annular recess (770) is formed between annular wall(754) and stand-off features (760). In some other versions, inner wallportions (766) extend fully to annular wall (754), such that annularwall (754) is connected directly to stand-off features (760) via innerwall portions (766).

Since each inner wall portion (766) is contiguous with a correspondingouter wall portion (762), and since the inner array of staple openings(724) is angularly offset from the inner array of staple openings (724),each stand-off feature (760) generally has a zig-zag configuration. Itshould also be understood that stand-off features (760) are discretelyformed in the present example, such that gaps are located between eachstand-off feature (760) and the adjacent stand-off features (760). Insome other versions, stand-off features (760) are contiguous with eachother.

In the version shown in FIG. 13 , the upper edges (768) of stand-offfeatures (760) are located above the plane of the upper edge of annularwall (754), such that upper edges (768) will contact tissue just beforeannular wall (754) contacts the tissue. In some other versions, at leasta portion of upper edges (768) are located along the same plane as theupper edge of annular wall (754), such that upper edges (768) andannular wall (754) will contact tissue along the same plane. In stillother versions, at least a portion of upper edges (768) are locatedbelow the plane of annular wall (754), such that annular wall (754) willcontact tissue just before upper edges (768) contact tissue.

FIG. 15 shows an exemplary cross-sectional profile that may be employedin first zone (710). In such versions, upper edges (768) in second zone(750) are located above the plane of the upper edge of annular wall(754). However, it should be understood that the cross-sectional profileshown in FIG. 15 may alternatively be employed in second zone (750). Insuch versions, upper edges (738) in first zone (710) are located belowthe plane of the upper edge of annular wall (754). In the presentexample, FIG. 15 shows how deck surface (722) is sloped downwardly fromthe outer region of deck member (702) toward the inner region of deckmember (702), along line (E). FIG. 15 also shows how upper edge (738) ofstand-off feature (730) and the upper edge of annular wall (754) allextend along the same curve (D). Of course, this configuration and setof relationships is just one merely illustrative example.

It should be understood that the protruding configuration of stand-offfeatures (760) relative to deck surface (752) will provide tissueengagement effects similar to those described above in the context ofdeck member (502). In particular, when tissue is compressed between deckmember (702) and anvil (400) as described above, portions of thecompressed tissue will enter the recessed areas adjacent to stand-offfeatures (760). By having some of the tissue enter these recessed areas,this may reduce the total pressure that would otherwise be applied tothe tissue if the tissue were being compressed against a consistentlyflat deck surface like deck surface (322). By reducing the totalpressure on the tissue, deck member (702) may reduce the risk of thetissue from becoming fractured by over-compression. In addition toreducing the total pressure on tissue, the entry of tissue portions inrecessed areas adjacent to stand-off features (760) may provide a gripon the compressed tissue that is greater than the grip that couldotherwise be achieved using a consistently flat deck surface like decksurface (322). The enhanced grip of tissue may promote cleaner cuttingby knife member (740) and also promote more successful deployment ofstaples (90) in the tissue. Thus, the presence of stand-off features(760) may both reduce the risk of over-compression of tissue and promotegreater success in cutting and stapling the tissue.

It should be understood that the above-described enhanced gripping andreduction of over-compression risk may also be provided in first zone(710). In particular, the protruding configuration of stand-off features(730) relative to deck surface (722) will provide some tissue engagementeffects, though such effects may be less pronounced in first zone (710)than in second zone (750). When tissue is compressed between deck member(702) and anvil (400) as described above, portions of the compressedtissue will enter the recessed areas adjacent to stand-off features(730). This may reduce the total pressure that would otherwise beapplied to the tissue if the tissue were being compressed against aconsistently flat deck surface like deck surface (322); and may alsoprovide a grip on the compressed tissue that is greater than the gripthat could otherwise be achieved using a consistently flat deck surfacelike deck surface (322). Thus, the presence of stand-off features (730)in first zone (710) may both reduce the risk of over-compression oftissue and promote greater success in cutting and stapling the tissue,within first zone (710).

In versions of first zone (710) having a cross-sectional profile likethe one shown in FIG. 15 , it should be understood that the tissueengagement effects may be more pronounced at the inner region of firstzone (710) than the tissue engagement effects at the outer region offirst zone (710). In other words, due to the combination of structuralfeatures being positioned along downwardly sloped line (E) andstructural features being positioned along curve (D), the tissueengagement effects of stand-off features (730) may progressivelyincrease from the outermost region of first zone (710) to the innermostregion of first zone (710).

As noted above, the entry of tissue into recessed areas adjacent tostand-off features (730, 760) may reduce the risk of over-compression oftissue and promote greater success in cutting and stapling the tissueduring actuation of anvil (400) and stapling head assembly (700).However, this same entry of tissue into recessed areas adjacent tostand-off features (760) may present some risks during insertion ofstapling head assembly (700) and shaft assembly (200) into tissue. Inother words, in variations of deck member (702) where the fullcircumference of deck member (502) is configured like second zone (750)of deck member (702), there may be a tendency for tissue (T) to enterthe recessed areas adjacent to stand-off features (760) during insertionof shaft assembly (200) and a stapling head assembly (700) into thepatient's colon (C). Any resulting snagging of tissue (T) on stand-offfeatures (760) may increase the risk of damage to tissue (T) in theevent that the tissue (T) is being pinched against the sacrum (S) asdescribed above with reference to FIG. 8 .

To avoid the above-noted risks that might otherwise be associated withtissue snagging on stand-off features (760) during insertion of shaftassembly (200) and stapling head assembly (500) into the patient's colon(C), first zone (710) is positioned to correspond with outer curve (214)of curved section (212) of shaft assembly (200). As shown in FIG. 8 ,the region of stapling head assembly (300) corresponding to outer curve(214) is the region of stapling head assembly (300) that would tend topinch the tissue (T) against the sacrum (S). It should be understoodthat the reduced effective height of stand-off features (730) relativeto stand-off features (760) may result in stand-off features (730)presenting a lower risk of stand-off features (730) pinching tissue (T)against the sacrum (S), as compared to the risk of such pinchingpresented by stand-Off features (760).

Thus, by having first zone (710) in the region of stapling head assembly(300) that would tend to pinch the tissue (T) against the sacrum (S),stapling head assembly (700) avoids the risks that might otherwise beassociated with stand-off features (760) during insertion of shaftassembly (200) and stapling head assembly (700) into the patient's colon(C); while still providing the advantages of stand-off features (760) insecond zone when anvil (400) and stapling head assembly (700) areactuated. Moreover, the presence of stand-off features (730) withinfirst zone (710) may still provide some of the same tissue engagementbenefits that are provided by stand-off features (760), though to asomewhat lesser degree than the tissue engagement benefits that areprovided by stand-off features (760).

C. Exemplary Deck Member with Combination of Connected and Non-ConnectedTissue Engagement Features

FIG. 16 shows a portion of an exemplary alternative stapling headassembly (800), which comprises a cylindraceous knife member (840) andan alternative deck member (850). Stapling head assembly (800) isconfigured and operable just like stapling head assembly (500, 600,700), except for the differences described below. In some versions, theangular region of deck member (850) shown in FIG. 16 corresponds withonly one portion of the full angular range of deck member (850). In someother versions, the angular region of deck member (850) shown in FIG. 16corresponds with the full angular range of deck member (850). Of course,deck member (850) may have any other kinds of geometries and structuralconfigurations along angular regions having any other arrangements andrelationships with the angular region represented in FIG. 16 .

Like deck member (502, 650, 702) described above, deck member (850) ofthe present example includes an inner annular array of staple openings(824) (shown as being closer to knife member (840)) and an outer annulararray of staple openings (824) (shown as being further from knife member(840)). While only one inner staple opening (824) and one outer stapleopening (824) are shown, it should be understood that additional stapleopenings (824) are provided in inner and outer annularly arrays that areangularly offset relative to each other, just like staple openings (524,724) of deck member (502, 702).

FIG. 16 also shows a first stand-off feature (880) surrounding theoutermost staple opening (824) and a second stand-off feature (860)surrounding the innermost staple opening (824). First stand-off feature(880) includes a curved outer wall (882) that inwardly and outwardlyterminates at deck surface (822). Deck surface (822) outwardlyterminates at a curved outer edge (820). A recess (870) is definedinboard of first stand-off feature (880), with deck surface (822)defining a sloped floor of recess (870). In particular, the regions ofdeck surface (822) that are inboard and outboard of first stand-offfeature (880) are oriented along a line (G), which slopes downwardlyfrom the outer region of deck member (802) toward the inner region ofdeck member (802). In some other versions, this line (G) is orientedperpendicularly relative to the longitudinal axis of stapling headassembly (800). In still other versions, this line (G) slopes upwardlyfrom the outer region of deck member (802) toward the inner region ofdeck member (802).

Second stand-off feature (860) includes an inclined upper surface (862)that outwardly terminates at deck surface (822) in recess (870). Uppersurface (862) inwardly terminates at inner wall (854) of deck member(802). While not shown, it should be understood that deck member (802)may also include a separate annular wall like annular walls (592, 654,754) described above, which may extend along the angular regions of deckmember (802) where second stand-off features (860) are angularly spacedapart from each other. In other words, stand-off features (860) may bediscretely positioned in an angularly spaced array, with stand-offfeatures (860) being integral with an annular wall that extends betweenthe discrete stand-off features (860).

As shown in FIG. 16 , the upper edge (824) of first stand-off feature(880) and upper surface (862) of second stand-off feature (860) extendalong the same plane, indicated by line (F). This line (F) slopesdownwardly from the outer region of deck member (802) toward the innerregion of deck member (802). In the present example, the slope of line(G) is steeper than the slope of line (F), though this relationship maybe reversed in some other versions. It should be understood that therelative orientations of lines (F, G) in this example results in secondstand-off feature (860) having a greater effective height than theeffective height of first stand-off feature (880). In some otherversions, first stand-off feature (880) has a greater effective heightthan the effective height of second stand-off feature (860).

It should be understood that the combination of stand-off features (860,880) and recess (870) may provide tissue engagement effects similar tothose described above. In particular, the combination of stand-offfeatures (860, 880) and recess (870) may provide enhanced gripping oftissue by deck member (802) while also providing a reduced pressureprofile against tissue that is compressed between anvil (400) and deckmember (802). To the extent that second stand-off features (860) have agreater effective height than the effective height of first stand-offfeatures (880), the tissue engagement effects may be more pronouncedtoward the inner region of deck member (802) as compared to the tissueengagement effects provided at the inner region of deck member (802).

It should also be understood that deck member (802) may include a zonewhere stand-off features (860, 880) are omitted or at least lesspronounced. Having such a zone may reduce the risk of deck member (802)snagging against tissue (T) as stapling head assembly (800) is beinginserted into the patient's colon. Similarly, having such a zone mayreduce the risk of deck member (802) damaging tissue (T) by pinching thetissue (T) against the sacrum (S) as stapling head assembly (800) isbeing inserted into the patient's colon (C). In such versions having a“no-snag” zone, the “no-snag” zone may be positioned to correspond withouter curve (214) of curved section (212) of shaft assembly (200).

D. Exemplary Deck Member with Tissue Engagement Features to Limit TissueFlow

In some instances when tissue is being compressed between anvil (400)and deck member (320), the tissue may tend to migrate or “flow,” ininward and/or outward radial directions, from the space between anvil(400) and deck member (320). In addition, or in the alternative, in someinstances when tissue is being compressed between anvil (400) and deckmember (320), the tissue may tend to migrate or flow in a twistingfashion, about the longitudinal axis of stapling head assembly (300) andanvil (400). It may therefore be desirable to provide a modified versionof deck member (320) with tissue engagement features that prevent orotherwise control the migration or flow of tissue in radial and angulardirections.

FIG. 17 shows an exemplary alternative deck member (900) that may beincorporated into stapling head assembly (300) in place of deck member(320). Deck member (900) of this example includes a deck surface (922)that defines an inner annular array of staple openings (924) and anouter annular array of staple openings (924). Deck member (900) furtherincludes an angularly spaced array of stand-off features (930).Stand-off features (930) are angularly spaced in an array about the fullcircumference of deck member (900) in this example. A correspondingangularly spaced array of radially extending channels (950) are formedbetween stand-off features (930). Channels (950) are tapered such thatchannels (950) have a larger angular width at the radially outer regionof deck member (900) than the angular width of channels (950) at theradially inner region of channels (950). Channels (950) pass over theouter array of staple openings (924), such that each channel (950) isassociated with a corresponding staple opening (924). It should beunderstood that some alternative versions of deck member (900) mayinclude a zone where stand-off features (930) are omitted or lesspronounced, etc.

Each stand-off feature (930) includes an angularly extending outerportion (932) and a set of radially extending inner portions (934). Eachouter portion (932) includes a curved outer edge (920). Each outerportion (932) also partially surrounds the angularly outermost ends ofadjacent staple openings (924). In particular, each outer portion (932)partially surrounds just one end of a corresponding first staple opening(924) while also partially surrounding just one end of a correspondingsecond staple opening (924). Thus, a single outer portion (932) does notsurround both ends of the same staple opening (924).

By contrast, each set of inner portions (934) for each stand-off feature(930) partially surrounds both of the angularly outermost ends ofadjacent staple openings (924). Inner portions (934) are tapered in thisexample, such that the inner portions (934) of each stand-off feature(930) define a corresponding tapered recess (940). Each recess (940)leads to a corresponding staple opening (924) in the inner array ofstaple openings (924). Recesses (940) are tapered such that each recess(940) has a larger angular width at the radially inner region of deckmember (900) than the angular width of recess (940) at the correspondstaple opening (924).

It should be understood that stand-off features (930) may provide tissueengagement features similar to those described above. In particular, thecombination of stand-off features (930), channels (950), and recesses(940) may provide enhanced gripping of tissue by deck member (900) whilealso providing a reduced pressure profile against tissue that iscompressed between anvil (400) and deck member (900). Moreover, theconfiguration of channels (950) and recesses (940) may minimize orotherwise control the migration or flow of tissue in inward and/oroutward radial directions, from the space between anvil (400) and deckmember (900), as the tissue is being compressed between anvil (400) anddeck member (900). Similarly, the configuration of channels (950) andrecesses (940) may prevent the migration or flow of tissue in a twistingfashion, about the longitudinal axis of stapling head assembly (300) andanvil (400), as the tissue is being compressed between anvil (400) anddeck member (900).

FIG. 18 shows another exemplary alternative deck member (1000) that maybe incorporated into stapling head assembly (300) in place of deckmember (320). Deck member (1000) of this example includes a deck surface(1022) that defines an inner annular array of staple openings (1024) andan outer annular array of staple openings (1024). Deck member (1000)further includes an angularly spaced array of stand-off features (1030).Stand-off features (1030) are angularly spaced in an array about thefull circumference of deck member (1000) in this example. Each stand-offfeature (1030) partially surrounds the end of one staple opening (1024)from the inner array of staple openings (1024) and one staple opening(1024) from the outer array of staple openings (1024). Each stand-offfeature (1030) also includes a curved outer end (1020). It should beunderstood that some alternative versions of deck member (1000) mayinclude a zone where stand-off features (1030) are omitted or lesspronounced, etc.

An angularly spaced array of radially extending first channels (1026)and an angularly spaced array of radially extending second channels(1028) are formed between stand-off features (1030). Channels (1026) areangularly interposed between channels (1028), such that channels (1026,1028) are arrayed in an alternating fashion. Channels (1026) are taperedsuch that each channel (1026) has a smaller angular width at theradially inner region of deck member (1000) than the angular width ofchannel (1026) at the radially outer region of deck member (1000). Bycontrast, channels (1028) are tapered such that each channel (1028) hasa larger angular width at the radially inner region of deck member(1000) than the angular width of channel (1028) at the radially outerregion of deck member (1000).

It should be understood that stand-off features (1030) may providetissue engagement features similar to those described above. Inparticular, the combination of stand-off features (930) and channels(1026, 1028) may provide enhanced gripping of tissue by deck member(1000) while also providing a reduced pressure profile against tissuethat is compressed between anvil (400) and deck member (1000). Moreover,the configuration of channels (1026, 1028) may minimize or otherwisecontrol the migration or flow of tissue in inward and/or outward radialdirections, from the space between anvil (400) and deck member (1000),as the tissue is being compressed between anvil (400) and deck member(1000). Similarly, the configuration of channels (1026, 1028) mayprevent the migration or flow of tissue in a twisting fashion, about thelongitudinal axis of stapling head assembly (300) and anvil (400), asthe tissue is being compressed between anvil (400) and deck member(1000).

E. Exemplary Deck Member with Tissue Engagement Recesses

FIGS. 19-20 show another exemplary alternative deck member (1100) thatmay be readily incorporated into stapling head assembly (300) in placeof deck member (320). Deck member (1100) of this example is configuredand operable just like deck member (320) except as otherwise describedbelow. Deck member (1100) of the present example comprises an innerannular array of staple openings (1124) and an outer annular array ofstaple openings (1124). Deck member (1124) further includes a first decksurface (1120), a second deck surface (1132), and a curved outer edge(1126). Staple openings (1124) are formed through second deck surface(1132), with first deck surface (1120) being located outboard of seconddeck surface (1132).

As best seen in FIG. 20 , second deck surface (1132) is proud relativeto first deck surface (1120), such that first deck surface (1120) isrecessed relative to second deck surface (1132). Portions of first decksurface (1120) extend inwardly relative in the spaces between the outerarray of staple openings (1124), thereby effectively forming recesses(1122) between staple openings (1124) of the outer array of stapleopenings (1124). In the present example, deck member (1100) furtherprovides angled transition surfaces (1134) between surfaces (1120,1132). In the present example, transition surfaces (1134) are flat andobliquely angled relative to surfaces (1120, 1132), thereby providing asloped transition between surfaces (1120, 1132). In some other versions,transition surfaces (1134) are curved. In some other versions,transition surfaces (1134) are perpendicular to surfaces (1120, 1132),thereby providing a steep step-down transition between surfaces (1120,1132).

Deck member (1100) of the present example further includes a set oftriangular recesses (1160) formed in second deck surface (1132). Eachtriangular recess (1160) includes a floor (1162) and three angledsidewalls (1164) providing a transition from deck surface (1132) tofloor (1162). In the present example, sidewalls (1164) are obliquelyangled relative to surface (1132) and floor (1162), thereby providing asloped transition from surface (1132) to floor (1162). In some otherversions, sidewalls (1164) are curved. In some other versions, sidewalls(1164) are perpendicular to surface (1132) and floor (1162), therebyproviding a steep step-down transition from surface (1132) to floor(1162). In the present example, and as best seen in FIG. 21 , floor(1162) is located on the same plane as first deck surface (1120). Insome other versions, floor (1162) is either higher or lower than firstdeck surface (1120).

As best seen in FIG. 19 , triangular recesses (1160) are configured andpositioned such that the outermost point of each triangular recess islocated between corresponding staple openings (1124) of the inner arrayof staple openings (1124). As also shown in FIG. 19 , deck member (1100)of the present example provides a first zone (1110) extending along afirst angular range of deck member (1100) and a second zone (1150)extending along a second angular range of deck member (1100). Triangularrecesses (1160) are included in second zone (1150) but not in first zone(1110). In some other variations, triangular recesses (1160) are arrayedalong the full angular extent of deck member (1000), such that there areno different zones (1110, 1150).

FIG. 21 shows how recesses (1122, 1160) provide engagement effects ontissue (L₁, L₂) that is being compressed between anvil (400) and deckmember (1100) within second zone (1150). In this depiction, an upperlayer of tissue (L₁) is adjacent to anvil (400) while a lower layer oftissue (L₂) is adjacent to deck member (1100), with both layers oftissue (L₁, L₂) also being adjacent to each other. As shown, a radiallyoutermost region of tissue (L_(2A)) enters recess (1122), a radiallyinnermost region of tissue (L_(2C)) enters triangular recess (1160), andan intermediate region of tissue (L_(2B)) is fully compressed againstsecond deck surface (1132). In other words, the compression of regionsof tissue (L_(2A), L_(2C)) is less than the compression of region oftissue (L_(2B)). It should be understood that the entry of regions oftissue (L_(2A), L_(2C)) may reduce the overall pressure applied totissue (L₁, L₂); and/or may provide an enhanced gripping effect ontissue (L₁, L₂).

It should be understood from the foregoing that recesses (1122, 1160)may provide tissue engagement effects that are similar to the tissueengagement effects described above as being provided by various kinds ofstand-off features. Moreover, by relying on recesses rather thanstand-offs to provide such tissue engagement effects, deck member (1100)may provide a further reduced risk of snagging tissue (T) duringinsertion of stapling head assembly (300) into the patient's colon (C).

F. Exemplary Deck Member Providing Variable Staple Height

FIG. 22 shows another exemplary stapling head assembly (1200) that maybe readily incorporated into instrument (10) in place of stapling headassembly (300). FIG. 22 also shows another exemplary anvil (1250) thatmay be used in place of anvil (400). Stapling head assembly (1200) andanvil (1250) are substantially identical to stapling head assembly (300)and anvil (400) described above, respectively, except for thedifferences described below. Stapling head assembly (1200) of thepresent example comprises pair of staples (1210, 1214) withcorresponding staple drivers (1212, 1216); a curved deck surface (1220);and a knife member (1204). In this example, staple (1214) has a greaterheight than staple (1210), and staple drivers (1212, 1216) arepositioned and configured to account for these differences in stapleheights. It should be understood that stapling head assembly (1200)includes an inner annular array of angularly spaced staples (1210) andcorresponding staple drivers (1212); and an outer annular array ofangularly spaced staples (1214) and corresponding staple drivers (1216).

The curvature of deck surface (1220) is contoured and positioned suchthat the outer region of deck surface (1220) is at a lower or moreproximal location than the inner region of deck surface (1220). Due tothis curvature, staple (1210) will exit deck surface (1220) at a point(c₁) that is distal to the point (c₂) at which staple (1214) will exitdeck surface (1220). Also, the curvature of deck surface (1220) willprovide variable pressure to the layers of tissue (L₃, L₄) compressedbetween deck surface (1220) and anvil (1250). Moreover, due to thecurvature of deck surface (1220), deck surface (1220) will tend tosqueeze the layers of tissue (L₃, L₄) radially outwardly as the layersof tissue (L₃, L₄) are compressed between deck surface (1220) and anvil(1250).

Anvil (1250) of the present example comprises a pair of staple formingpockets (1254, 1256). Staple forming pocket (1254) is positioned tocorrespond with staple (1210) while staple forming pocket (1214) ispositioned to correspond with staple (1214). Staple forming pocket(1254) is located at a position (a₁) that is proximal relative to theposition (a₂) at which staple forming pocket (1256) is located. Anvil(1250) also includes a breakable washer (1252), which is similar tobreakable washer (417) as described above. In particular, washer (1252)is broken by knife member (1204) when knife member (1204) completes afull distal range of motion upon actuation of stapling head assembly(1200).

FIG. 23 shows layers of tissue (L₃, L₄) after stapling head assembly(1200) has been actuated to sever and staple the tissue (L₃, L₄). Inparticular, FIG. 23 shows staple (1210) deployed in an inner region oftissue (L₃, L₄), with staple (1214) being deployed in an outer region oftissue (L₃, L₄). The deployed staple (1210) has a height (x₁) that isshorter than the height (x₂) of deployed staple (1214). This is due tothe fact that unformed staple (1210) was shorter than unformed staple(1214), the exit point (c₁) of staple (1210) is distal in relation tothe exit point (c₂) of staple (1214), and the position (a₁) of stapleforming pocket (1254) is proximal in relation to the position (a₂) ofstaple forming pocket (1256). It should be understood that, by providingthese varied heights (x₁, x₂), deployed staples (1210, 1214) maymaintain the varied pressure profile that was applied against layers oftissue (L₃, L₄) by curved deck surface (1220) and the correspondingsurface of anvil (1250).

G. Exemplary Staple Deck Member with Combination of Rigid andElastomeric Features

FIGS. 24-26 show another exemplary stapling head assembly (1300) thatmay be readily incorporated into instrument (10) in place of staplinghead assembly (300). Stapling head assembly (1300) is substantiallyidentical to stapling head assembly (500) described above, except forthe differences described below. Stapling head assembly (1300) of thepresent example comprises a deck member (1350) having a deck surface(1352) that defines two concentric annular arrays of staple openings(1324). Staple openings (1324) are arranged to correspond with thearrangement of staple drivers (352) and staple forming pockets (414)described above. Thus, each staple opening (1324) is configured toprovide a path for a corresponding staple driver (352) to drive acorresponding staple (90) through deck member (1350) and into acorresponding staple forming pocket (414) when stapling head assembly(1300) is actuated. Deck member (1350) defines an inner diameter that isjust slightly larger than the outer diameter defined by knife member(1340). Deck member (1350) is thus configured to allow knife member(1340) to translate distally to a point where cutting edge (1342) isdistal to deck surface (1352).

In the present example, a plurality of stand-off features (1360)protrude upwardly from deck surface (1352). Stand-off features (1360)each comprise a wall (1364) that partially wraps around an end of aninner staple opening (1324) and an end of an outer staple opening(1324), with a zig-zag configuration that is identical to theconfiguration of stand-off features (560) described above.

Deck member (1350) of the present example also includes an upwardlyprotruding annular wall (1354). Annular wall (1354) of this example isconfigured and operable identically to annular wall (592) describedabove. An annular recess (1390) is formed between annular wall (1354)and stand-off features (1360). In some other versions, annular wall(1354) is connected directly to stand-off features (1360). It shouldalso be understood that deck member (1350) may be divided into zoneslike the zones described above. For instance, deck member (1350) mayhave stand-off features (1360) located in one angular region of deckmember (1350) (e.g., similar to zones (550, 750) described above); withanother angular region of deck member (1350) either being flat (e.g.,similar to zone (510) described above) or having less-pronouncedversions of stand-off features (1360) (e.g., similar to zone (710)described above. Alternatively, stand-off features (1360) may extendaround the full angular range of deck member (1350).

It should also be understood that stand-off features (1360) may providetissue engagement effects similar to those provided by other tissueengagement features described herein, including but not limited tostand-off features (560). Thus, stand-off features (1360) may reduce thetotal pressure that would otherwise be applied to tissue compressedagainst deck member (1350), enhance the gripping of tissue that iscompressed against deck member (1350), and/or provide other tissueengagement effects.

In contrast to stand-off features (560) described above, stand-offfeatures (1360) of the present example are partially deformable. Inparticular, an outer region of stand-off features (1360) is formedprimarily by an elastomeric member (1370) while an inner region ofstand-off features (1360) is formed primarily by a rigid base member(1380). As best seen in FIG. 25 , deck member (1350) provides a slopedinterface between rigid base member (1380) and elastomeric member(1370), such that the inner region of elastomeric member (1370) isthinner than the outer region of elastomeric member (1370), with wall(1364) still providing a flat distal surface trough which staples (90)exit.

FIG. 26 shows anvil (400) compressing layers of tissue (L₅, L₆) againstdeck member (1350). As shown, elastomeric member (1370) compressiblydeforms against layer of tissue (L₆). It should be understood that evenwith elastomeric member (1370) being compressible, stand-off features(1360) may still provide an enhanced grip of tissue (L₆) at least duringan initial stage of compression of tissue (L₅, L₆). The rigidity of basemember (1380), combined with the reduced thickness of elastomeric member(1370) at the inner region of stand-off features (1360), and thepresence of recess (1390), may further provide an enhanced grip oftissue (L₆) during the full range of compression of tissue (L₅, L₆). Thedeformation of elastomeric member (1370) may further allow deck member(1350) to provide a pressure profile against layers of tissue (L₅, L₆)that varies along the radial extent of deck member (1350). Inparticular, deck member (1350) may provide greater compression of tissue(L₅, L₆) at the inner region of deck member (1350) as compared to theouter region of deck member (1350). This varying compression may furthersqueeze tissue (L₅, L₆) radially outwardly as tissue (L₅, L₆) is beingcompressed between deck member (1350) and anvil (400).

In addition to providing a different tissue gripping profile and avarying pressure profile against tissue, elastomeric member (1370) mayalso reduce the risk of stand-off features (1360) snagging on tissue (T)as stapling head assembly (1300) is inserted into a patient's colon (C).In particular, in the event that the outer regions of stand-off features(1360) encounter a fold (F) of tissue (T) or a region of tissue (T) thatis adjacent to the patient's sacrum (S), elastomeric member (1370) maysimply deform to absorb the forces impinged against stand-off features(1360). Thus, the inclusion of elastomeric member (1370) may provide areduced risk of tissue damage as compared to the risk posed by versionsof stand-off features (1360) that are entirely rigid.

H. Exemplary Staple Deck Member with Combination of Rigid andElastomeric Features

FIGS. 27-28 show another exemplary stapling head assembly (1400) thatmay be readily incorporated into instrument (10) in place of staplinghead assembly (300). Stapling head assembly (1400) is substantiallyidentical to stapling head assembly (300) described above, except forthe differences described below. Stapling head assembly (1400) of thepresent example comprises a curved deck surface (1450) presenting arounded outer edge (1420). A plurality of staple openings (1424) areformed through deck surface (1450).

While deck surface (1450) has a generally curved profile in thisexample, deck surface (1450) defines a set of flat surfaces (1434, 1436,1438) adjacent to staple openings (1424). In particular, flat surfaces(1434) are located inboard of each inner staple opening (1424). Flatsurfaces (1436) are located inboard of each outer staple opening (1424).Each flat surface (1436, 1434) is adjacent to a corresponding inner wall(132) that leads to an inner annular portion (1430). Inner annularportion (1430) is configured to function similar to annular wall (592),such that inner annular portion (1430) is configured to compress apartially annular region of tissue against anvil (400), therebyproviding assistance for edge (1404) of knife member (1402) to sheartissue. Flat surfaces (1438) are located outboard of each inner andouter staple opening (1424). Flat surfaces (1438) transition directly torounded outer edge (1420).

Deck surface (1450) also defines a zig-zag wall (1452) that partiallywraps around ends of staple openings (1424). It should be understoodthat the recessed aspect of flat surfaces (1434, 1436, 1438) relative towalls (1452) will provide regions for tissue to enter as the tissue iscompressed against deck surface (1450) by anvil (400). Thus, zig-zagwalls (1452) may provide tissue engagement effects similar to thosedescribed above, including reducing the total pressure that wouldotherwise be applied to tissue compressed against deck member (1450),enhancing the gripping of tissue that is compressed against deck member(1450), and/or providing other tissue engagement effects.

It should also be understood that the curved profile of deck surface(1450) may provide effects similar to those described above with respectto deck surface (1220). In particular, the curvature of deck surface(1450) may provide variable pressure to the tissue compressed betweendeck surface (1450) and anvil (400). Moreover, due to the curvature ofdeck surface (1450), deck surface (1450) may tend to squeeze the tissueradially outwardly as the tissue is compressed between deck surface(1450) and anvil (400).

I. Exemplary Staple Deck Member with Tissue Engagement Features andStaple Driver Guard Features

In some conventional circular staplers, there may be a tendency forfeatures of an actuated staple driver to protrude distally from the decksurface of the stapling head assembly after the stapling head assemblyhas been actuated. In some instances, these protruding staple driverfeatures may be sharp or have some other structural configuration thatmay tend to damage tissue. This risk of tissue damage from exposedfeatures of staple driver features may be present immediately after thestapling head assembly is actuated (i.e., the exposed staple driverfeatures may damage the tissue that is still compressed between theanvil and the staple deck). In addition, there may be a risk that suchstaple driver features will snag on tissue as the actuated stapling headassembly is removed from the patient's colon (C) or other anatomicalstructure. It may therefore be desirable to modify the deck of thestapling head assembly to prevent any features of an actuated stapledriver to protrude distally from the deck surface after the staplinghead assembly has been actuated.

FIG. 29 shows another exemplary alternative deck member (1500) that maybe readily incorporated into stapling head assembly (300) in place ofdeck member (320). Deck member (1500) of this example comprises a decksurface (1510) defining a plurality of staple openings (1524). Decksurface (1510) includes a zig-zag walls (1512) and an inner annularportion (1514). Zig-zag walls (1512) partially wrap around ends ofstaple openings (1424). Inner annular portion (1514) is configured tofunction similar to annular wall (592), such that inner annular portion(1514) is configured to compress a partially annular region of tissueagainst anvil (400), thereby providing assistance for a cutting edge ofa knife member to shear tissue. Deck surface (1510) further defines aninner recess (1540) inboard of each inner staple opening (1524) and anouter recess (1544) that is outboard of each inner staple opening(1524). Similarly, deck surface (1510) further defines an inner recess(1542) inboard of each outer staple opening (1524) and an outer recess(1546) that is outboard of each outer staple opening (1524). Outerrecesses (1544, 1546) are contiguous with a rounded outer edge (1520) ofdeck member (1500). Deck member (1550) also includes a set of innerwalls (1550) separating each inner staple opening (1524) fromcorresponding recesses (1540, 1544). Inner walls (1550) are recessedrelative to deck surface (1510) but are proud relative to recesses(1540, 1544). Similarly, a set of wall (1550) separates each outerstaple opening (1524), from corresponding recesses (1542, 1546). Again,inner walls (1550) are recessed relative to deck surface (1510) but areproud relative to recesses (1542, 1546).

It should be understood that the combination of zig-zag walls (1512) andrecesses (1540, 1542, 1544, 1546) may provide tissue engagement effectssimilar to those described above, including reducing the total pressurethat would otherwise be applied to tissue compressed against deck member(1500), enhancing the gripping of tissue that is compressed against deckmember (1500), and/or providing other tissue engagement effects.

It should also be understood that zig-zag walls (1512) and walls (1550)may cooperate to shield deployed staple drivers (1502). In particular,as shown in FIG. 29 , all of the structural features of the deployedstaple drivers (1502) are recessed relative to zig-zag walls (1512) andwalls (1550) in this example. Zig-zag walls (1512) and walls (1550) willthus prevent staple drivers (1502) from snagging or otherwise damagingtissue after staple drivers (1502) have reached the fully deployedposition shown in FIG. 29 .

III. Exemplary Combinations

The following examples relate to various non-exhaustive ways in whichthe teachings herein may be combined or applied. It should be understoodthat the following examples are not intended to restrict the coverage ofany claims that may be presented at any time in this application or insubsequent filings of this application. No disclaimer is intended. Thefollowing examples are being provided for nothing more than merelyillustrative purposes. It is contemplated that the various teachingsherein may be arranged and applied in numerous other ways. It is alsocontemplated that some variations may omit certain features referred toin the below examples. Therefore, none of the aspects or featuresreferred to below should be deemed critical unless otherwise explicitlyindicated as such at a later date by the inventors or by a successor ininterest to the inventors. If any claims are presented in thisapplication or in subsequent filings related to this application thatinclude additional features beyond those referred to below, thoseadditional features shall not be presumed to have been added for anyreason relating to patentability.

Example 1

An apparatus comprising: (a) a body; (b) a shaft assembly extendingdistally from the body, wherein the shaft assembly has a distal end; (c)a stapling head assembly located at the distal end of the shaftassembly, wherein the stapling head assembly comprises: (i) an annulardeck member defining an inner diameter and an outer diameter, whereinthe deck member comprises: (A) a first deck surface, wherein the firstdeck surface has a curved profile defined by a curve extending from theinner diameter of the deck member to the outer diameter of the deckmember, (B) an outer annular array of staple openings, and (C) an innerannular array of staple openings, (ii) a plurality of staples, and (iii)a driver operable to drive the staples through the staple openings; and(d) an anvil, wherein the anvil is operable to compress tissue againstthe first deck surface.

Example 2

The apparatus of Example 1, wherein the curve presents a distal-mostregion located between the inner diameter and the outer diameter.

Example 3

The apparatus of Example 2, wherein the distal-most region of the curveis located closer to the inner diameter than to the outer diameter.

Example 4

The apparatus of any one or more of Examples 1 through 3, wherein thedeck member further comprises a second deck surface, wherein the seconddeck surface is recessed relative to the first deck surface.

Example 5

The apparatus of Example 4, wherein the deck member further comprises aplurality of stand-off features protruding from the second deck surface,wherein the first deck surface is located on the stand-off features.

Example 6

The apparatus of Example 5, wherein the stand-off features comprisewalls having a zig-zag shape.

Example 7

The apparatus of any one or more of Examples 5 through 6, wherein aninner portion of each stand-off feature partially surrounds an end of acorresponding staple opening of the inner annular array of stapleopenings, wherein an outer portion of each stand-off feature partiallysurrounds an end of a corresponding staple opening of the outer annulararray of staple openings.

Example 8

The apparatus of any one or more of Examples 5 through 7, furthercomprising an inner annular wall extending upwardly from the secondsurface, wherein the inner annular wall is located at the inner diameterof the deck member.

Example 9

The apparatus of Example 8, wherein a portion of the first surface and adistal edge of the inner annular wall are coplanar.

Example 10

The apparatus of any one or more of Examples 8 through 9, wherein thedeck member defines an annular recess between the stand-off features andthe inner annular wall.

Example 11

The apparatus of any one or more of Examples 8 through 10, wherein theinner annular wall has a distal edge, wherein the distal edge of theannular wall is located along the curve of the first deck surface.

Example 12

The apparatus of any one or more of Examples 4 through 11, wherein thestapling head assembly defines a longitudinal axis, wherein second decksurface is obliquely oriented relative to the longitudinal axis.

Example 13

The apparatus of Example 12, wherein the second deck surface isobliquely oriented such that an outermost portion of the second decksurface is positioned distally relative to an innermost portion of thedeck surface, such that the second deck surface slopes proximally fromthe outermost portion toward the innermost portion.

Example 14

The apparatus of any one or more of Examples 1 through 13, wherein thedeck member further comprises a second deck surface extending along afirst angular range, wherein the second deck surface is flat, whereinthe first deck surface extends along a second angular range.

Example 15

The apparatus of Example 14, wherein the shaft assembly has a curvedregion with an inner curve and an outer curve, wherein the first angularrange is angularly positioned to correspond with the outer curve,wherein the second angular range is angularly positioned to correspondwith the inner curve.

Example 16

An apparatus, comprising: (a) a body; (b) a shaft assembly extendingdistally from the body, wherein the shaft assembly has a distal end; (c)a stapling head assembly located at the distal end of the shaftassembly, wherein the stapling head assembly defines a longitudinalaxis, wherein the stapling head assembly comprises: (i) an annular deckmember defining an inner diameter and an outer diameter, wherein thedeck member comprises: (A) a deck surface, wherein a portion of the decksurface is obliquely oriented relative to the longitudinal axis suchthat the deck surface is sloped along a radially extending path, (B) anouter annular array of staple openings, and (C) an inner annular arrayof staple openings, (ii) a plurality of staples, and (iii) a driveroperable to drive the staples through the staple openings; and (d) ananvil, wherein the anvil is operable to compress tissue against thefirst deck surface.

Example 17

The apparatus of Example 16, wherein the deck surface is sloped suchthat the deck surface slopes proximally from an outer region of the decksurface toward an inner region of the deck surface.

Example 18

The apparatus of any one or more of Examples 16 through 17, wherein thedeck member further comprises a distal surface positioned distally inrelation to the deck surface.

Example 19

The apparatus of Example 18, wherein the distal surface has a curvedprofile defined by a curve extending from the inner diameter of the deckmember to the outer diameter of the deck member.

Example 20

A surgical stapling head assembly, comprising: (a) an annular deckmember defining an inner diameter and an outer diameter, wherein thedeck member comprises: (i) a first deck surface, wherein the first decksurface has a curved profile defined by a curve extending from the innerdiameter of the deck member to the outer diameter of the deck member,(ii) a second deck surface, wherein a portion of the deck surface isobliquely oriented relative to the longitudinal axis such that the decksurface is sloped along a radially extending path, (iii) an outerannular array of staple openings, and (iv) an inner annular array ofstaple openings; (b) a plurality of staples; and (c) a driver operableto drive the staples through the staple openings.

IV. Miscellaneous

It should be understood that the teachings above may be readily combinedwith the teachings of U.S. patent application Ser. No. 15/350,513,entitled “Circular Surgical Stapler with Recessed Deck,” filed on Nov.14, 2016, issued as U.S. Pat. No. 10,980,542 on Apr. 20, 2021, thedisclosure of which is incorporated by reference herein. Varioussuitable ways in which the teachings herein and the teachings of U.S.patent application Ser. No. 15/350,513 may be combined will be apparentto those of ordinary skill in the art.

It should also be understood that the teachings above may be readilycombined with the teachings of U.S. patent application Ser. No.15/350,621, entitled “Staple Forming Pocket Configurations for CircularSurgical Stapler Anvil,” filed on Nov. 14, 2016 now abandoned, thedisclosure of which is incorporated by reference herein. Varioussuitable ways in which the teachings herein and the teachings of U.S.patent application Ser. No. 15/350,621 may be combined will be apparentto those of ordinary skill in the art.

It should also be understood that the teachings above may be readilycombined with the teachings of U.S. patent application Ser. No.15/350,624, entitled “Circular Surgical Stapler with AngularlyAsymmetric Deck Features,” filed on Nov. 14, 2016, issued as U.S. Pat.No. 10,603,041 on Mar. 31, 2020, the disclosure of which is incorporatedby reference herein. Various suitable ways in which the teachings hereinand the teachings of U.S. patent application Ser. No. 15/350,624 may becombined will be apparent to those of ordinary skill in the art.

It should also be understood that any one or more of the teachings,expressions, embodiments, examples, etc. described herein may becombined with any one or more of the other teachings, expressions,embodiments, examples, etc. that are described herein. Theabove-described teachings, expressions, embodiments, examples, etc.should therefore not be viewed in isolation relative to each other.Various suitable ways in which the teachings herein may be combined willbe readily apparent to those of ordinary skill in the art in view of theteachings herein. Such modifications and variations are intended to beincluded within the scope of the claims.

At least some of the teachings herein may be readily combined with oneor more teachings of U.S. Pat. No. 7,794,475, entitled “Surgical StaplesHaving Compressible or Crushable Members for Securing Tissue Therein andStapling Instruments for Deploying the Same,” issued Sep. 14, 2010, thedisclosure of which is incorporated by reference herein; U.S. Pub. No.2014/0151429, entitled “Trans-Oral Circular Anvil Introduction Systemwith Dilation Feature,” published Jun. 5, 2014, issued as U.S. Pat. No.9,572,573 on Feb. 21, 2017, the disclosure of which is incorporated byreference herein; U.S. Pub. No. 2014/0144968, entitled “Surgical Staplewith Integral Pledget for Tip Deflection,” published May 29, 2014,issued as U.S. Pat. No. 9,289,207 on Mar. 22, 2016, the disclosure ofwhich is incorporated by reference herein; U.S. Pub. No. 2014/0158747,entitled “Surgical Stapler with Varying Staple Widths along DifferentCircumferences,” published Jun. 12, 2014, now abandoned, the disclosureof which is incorporated by reference herein; U.S. Pub. No.2014/0144969, entitled “Pivoting Anvil for Surgical Circular Stapler,”published May 29, 2014, issued as U.S. Pat. No. 9,498,222 on Nov. 22,2016, the disclosure of which is incorporated by reference herein; U.S.Pub. No. 2014/0151430, entitled “Circular Anvil Introduction System withAlignment Feature,” published Jun. 5, 2014, issued as U.S. Pat. No.9,724,100 on Aug. 8, 2017, the disclosure of which is incorporated byreference herein; U.S. Pub. No. 2014/0166717, entitled “Circular Staplerwith Selectable Motorized and Manual Control, Including a Control Ring,”published Jun. 19, 2014, issued as U.S. Pat. No. 9,532,783 on Jan. 3,2017, the disclosure of which is incorporated by reference herein; U.S.Pub. No. 2014/0166728, entitled “Motor Driven Rotary Input CircularStapler with Modular End Effector,” published Jun. 19, 2014, issued asU.S. Pat. No. 9,597,081 on Mar. 21, 2017, the disclosure of which isincorporated by reference herein; and/or U.S. Pub. No. 2014/0166718,entitled “Motor Driven Rotary Input Circular Stapler with LockableFlexible Shaft,” published Jun. 19, 2014, issued as U.S. Pat. No.9,463,022 on Oct. 11, 2016, the disclosure of which is incorporated byreference herein. Various suitable ways in which such teachings may becombined will be apparent to those of ordinary skill in the art.

It should be appreciated that any patent, publication, or otherdisclosure material, in whole or in part, that is said to beincorporated by reference herein is incorporated herein only to theextent that the incorporated material does not conflict with existingdefinitions, statements, or other disclosure material set forth in thisdisclosure. As such, and to the extent necessary, the disclosure asexplicitly set forth herein supersedes any conflicting materialincorporated herein by reference. Any material, or portion thereof, thatis said to be incorporated by reference herein, but which conflicts withexisting definitions, statements, or other disclosure material set forthherein will only be incorporated to the extent that no conflict arisesbetween that incorporated material and the existing disclosure material.

Versions of the devices described above may have application inconventional medical treatments and procedures conducted by a medicalprofessional, as well as application in robotic-assisted medicaltreatments and procedures. By way of example only, various teachingsherein may be readily incorporated into a robotic surgical system suchas the DAVINCI™ system by Intuitive Surgical, Inc., of Sunnyvale,California.

Versions described above may be designed to be disposed of after asingle use, or they can be designed to be used multiple times. Versionsmay, in either or both cases, be reconditioned for reuse after at leastone use. Reconditioning may include any combination of the steps ofdisassembly of the device, followed by cleaning or replacement ofparticular pieces, and subsequent reassembly. In particular, someversions of the device may be disassembled, and any number of theparticular pieces or parts of the device may be selectively replaced orremoved in any combination. Upon cleaning and/or replacement ofparticular parts, some versions of the device may be reassembled forsubsequent use either at a reconditioning facility, or by a userimmediately prior to a procedure. Those skilled in the art willappreciate that reconditioning of a device may utilize a variety oftechniques for disassembly, cleaning/replacement, and reassembly. Use ofsuch techniques, and the resulting reconditioned device, are all withinthe scope of the present application.

By way of example only, versions described herein may be sterilizedbefore and/or after a procedure. In one sterilization technique, thedevice is placed in a closed and sealed container, such as a plastic orTYVEK bag. The container and device may then be placed in a field ofradiation that can penetrate the container, such as gamma radiation,x-rays, or high-energy electrons. The radiation may kill bacteria on thedevice and in the container. The sterilized device may then be stored inthe sterile container for later use. A device may also be sterilizedusing any other technique known in the art, including but not limited tobeta or gamma radiation, ethylene oxide, or steam.

Having shown and described various embodiments of the present invention,further adaptations of the methods and systems described herein may beaccomplished by appropriate modifications by one of ordinary skill inthe art without departing from the scope of the present invention.Several of such potential modifications have been mentioned, and otherswill be apparent to those skilled in the art. For instance, theexamples, embodiments, geometries, materials, dimensions, ratios, steps,and the like discussed above are illustrative and are not required.Accordingly, the scope of the present invention should be considered interms of the following claims and is understood not to be limited to thedetails of structure and operation shown and described in thespecification and drawings.

1.-20. (canceled)
 21. An apparatus comprising: (a) a shaft assemblycomprising a distal end; and (b) a stapling assembly coupled with theshaft assembly, wherein the stapling assembly comprises: (i) an anvil,(ii) a knife, (iii) a deck member defining a central knife opening,wherein the knife actuatable through the central knife opening, whereinthe deck member comprises: (A) an outer edge, (B) a deck surfaceextending between the central knife opening and the outer edge, whereinthe deck surface defines a first array of staple openings and a secondarray of staple openings, wherein the first array of staple openings iscloser to the central knife opening compared to the second array ofstaple openings, and (C) at least one stand-off feature extendingupwardly from the deck surface, wherein the at least one stand-offfeature surrounds a respective one or more staple openings of the firstarray of staple openings and the second array of staple openings, and(iv) a plurality of staples, wherein each staple of the plurality ofstaples is associated with a respective staple opening of either thefirst array of staple openings or the second array of staple openings,wherein the at least one stand-off feature comprises a height thatvaries in a direction extending transversely between the central knifeopening and the outer edge of the deck member.
 22. The apparatus ofclaim 21, wherein at least one stand-off feature comprises a zig-zagwall that partially wraps around a first staple opening associated withthe first array of staple openings and a second staple openingassociated with the second array of staple openings.
 23. The apparatusof claim 22, wherein the deck surface comprises a plurality of flatsurfaces.
 24. The apparatus of claim 23, wherein the outer edgecomprises a rounded outer edge.
 25. The apparatus of claim 21, whereinthe at least one stand-off feature comprises a rounded top surface thatvaries the height of the at least one stand-off feature.
 26. Theapparatus of claim 21, wherein the at least one stand-off featureextends between a first staple opening associated with the first arrayof staple openings and a second staple opening associated with thesecond array of staple openings.
 27. The apparatus of claim 26, whereinthe at least one stand-off feature partially defines the first stapleopening and the second staple opening.
 28. The apparatus of claim 27,wherein the at least one stand-off feature directly extends into theouter edge and a portion of the deck member defining the central knifeopening.
 29. The apparatus of claim 21, wherein the deck surface extendsbetween the outer edge and the central knife opening along a verticalslope.
 30. The apparatus of claim 29, wherein a first portion of thedeck surface adjacent to the central knife opening is lower than asecond portion of the deck surface adjacent to the outer edge.
 31. Theapparatus of claim 21, wherein a first portion of the at least onestand-off features adjacent to the central knife opening is taller thana second portion of the at least one stand-off feature adjacent to theouter edge.
 32. The apparatus of claim 31, wherein a central portion ofthe at least one stand-off feature is taller than both the first portionand the second portion.
 33. The apparatus of claim 21, wherein the knifecomprises a cylindrical knife.
 34. The apparatus of claim 21, whereinthe first array of staple openings extend along an annular profile. 35.The apparatus of claim 21, wherein the anvil is configured toselectively couple to the rest of the stapling assembly.
 36. Anapparatus comprising: (a) a shaft assembly comprising a distal end; and(b) a stapling assembly coupled with the shaft assembly, wherein thestapling assembly comprises: (i) an anvil, (ii) a deck member defining acentral opening, wherein the deck member comprises: (A) an outer edge,(B) a deck surface extending between the central opening and the outeredge, wherein the deck surface defines a plurality of staple openings,wherein the plurality of staple openings comprises a first stapleopening and a second staple opening, wherein the first staple opening iscloser to the central opening compared to the second staple opening, and(C) a stand-off feature extending upwardly from the deck surface,wherein the stand-off feature surrounds a portion of the first stapleopening and the second staple opening, and (iii) a plurality of staples,wherein each staple of the plurality of staples is housed within arespective staple opening of the plurality of staple openings, whereinthe stand-off feature extends between the outer edge and the centralopening and between the first staple opening and the second stapleopening, wherein the stand-off feature varies in height along a pathextending transversely between the outer edge and the central opening.37. The apparatus of claim 36, wherein the stand-off feature comprises arounded profile.
 38. The apparatus of claim 37, wherein the deck surfacecomprises a plurality of flat surfaces.
 39. The apparatus of claim 36,further comprising a cylindrical knife slidably housed within thecentral opening.
 40. An apparatus comprising: (a) a shaft assemblycomprising a distal end; and (b) a stapling assembly coupled with theshaft assembly, wherein the stapling assembly comprises: (i) an anvil,(ii) a deck member defining a knife opening, wherein the deck membercomprises: (A) an outer edge, (B) a deck surface extending between theknife opening and the outer edge, the deck surface defining a firstarray of staple openings and a second array of staple openings, whereinthe first array of staple openings is closer to the knife openingcompared to the second array of staple openings, and (B) at least onestand-off feature extending upwardly from the deck surface and locatedbetween the first array of staple openings and the second array ofstaple openings, and (iii) a plurality of staples associated withrespective staple openings of the first array of staple openings and thesecond array of staple openings, wherein the at least one stand-offfeature comprises a height that changes as the at least one stand-offfeature extends transversely between the outer edge and the knifeopening.